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Polysiloxanes have been found to be the most important and commercial family of synthetic inorganic polymers. The unique structure of the siloxane bond provides them with unusual features such as a high bond angle, nearly inexistent torsional barrier and a semi-ionic character due to the difference of electronegativities between the silicon and oxygen atoms. Also, silicon-based polymers have been used for the delivery of pharmaceutical and diagnostic compounds involving the use of nanoparticles with different shapes and sizes, as well as hydrogels, including those based on silicon compounds. Hydrogels based on silicon polyolates are rather promising. Some of them exhibit pronounced anti-inflammatory, regenerating, and protective activity, readily penetrate the organism and facilitate drug penetration into the tissues. Due to these properties, polysiloxanes have encountered a big opportunity as an important material in the area of biomedical engineering; the big influence they have in the area of prosthetic dentistry, tissue engineering, cell growth, wounded skin treatments is noteworthy. For the reasons briefly described above, we consider the fact of doing a review about how the polysiloxanes have been used over the years as polymeric matrices that are used in several applications in the field of biomedical engineering.

The creation of films constituted by semiconductor oxides of zinc oxide (ZnO) incorporated into a polar polymer matrix was proposed, looking for such films to be easy to apply, friendly to the environment and compatible with materials. Within the experimental process, the synthesis of styrene copolymers with a polar monomer (methyl methacrylate) was carried out through the suspension and emulsion polymerization processes.

In the ambit of the synthesis of silicon polymers and elastomers, there are a lot of variables that affect the final properties of the material, and consequently, their applications. In this work, we synthetized polymethylhydrogensiloxane using the ring opening polymerization (ROP) with 2,4,6,8-tetramethylcyclotetrasiloxane as monomer (D4H), a synthetic aluminosilicate like catalytic species and hexamethyldisiloxane as chain blocker. We made a set of experiments, in order to find the effect on the reaction yield, the absence of crosslinking, crosslinking degree and the mechanical properties of the final polymers. We found that the factor “chain blocker addition time” is significant for yield reaction and crosslinking degree of the elastomers, obtaining a greater crosslinking degree and reaction yield when is added at the beginning of the reaction. Also, using DSC measurements, we found an endothermal signal in 553 K corresponding to the elastomer’s chains rearrangement to dissipate the heat supplied. We obtained PMHS chains up to 24,270 g/mol indicating the ability of this kind of catalysts to achieve relatively high molecular weight chains.

Strategies for extracting organic acids from aqueous solutions using polymeric absorbents are demonstrated and discussed in the context of two-phase partitioning bioreactor (TPPB) design. Experimental data and material balances for the uptake of butyric acid and benzoic acid by a poly(ether-block-amide) copolymer (Pebax 2533) establish the inherent limitations of unreactive absorbents for organic acid bioprocesses that operate at near-neutral pH. Improvements to TPPB performance are achieved by lowering pH temporarily with CO2 to enhance acid absorption, and removing the solute-rich polymer before restoring pH to fermentative values by releasing the CO2 pressure. Butyric acid removal by Pebax 2533 improved from 3% to 40% upon acidifying a pH 6 solution with 60 bar of CO2, while benzoic acid absorption increased from 1% to 80% using this pressure manipulation technique. A reactive extraction approach involving a newly-synthesized amine functionalized hydrogel is also described wherein acid/base reaction equilibrium governs the extent of solute uptake. Copolymerization of 2-(dimethylamino)ethyl acrylate (DMAEA) and trimethylolpropane triacrylate (TMPTA) yielded a thermoset material with sufficient basicity to remove 80% of both butyric and benzoic acid from aqueous solution using just 1 wt% polymer relative to the aqueous phase mass.

Pulsed-laser polymerization combined with polymer analysis by NMR and size-exclusion chromatography is used to study the radical copolymerization kinetics of isoprene (IP) with glycidyl methacrylate (GMA). The copolymer is characterized by a close-to-alternating microstructure, with the addition of IP leading to a significant decrease in the composition-averaged propagation rate coefficient. A rigorous fitting strategy is developed to fit a mixed penultimate model to the data, with the selectivity of the IP, but not the GMA, macroradical dependent on the penultimate unit.